Well jet device for testing and studying formations and the operating method thereof

ABSTRACT

The invention relates to jet devices and the operating methods thereof and can be used in order to produce and intensify the oil inflow from a well. The inventive device comprises a jet pump arranged on a tubing string in the well with a casing string. An active nozzle and a mixing chamber are coaxially arranged in the body of said pump and a bypass channel provided with a mounting seat for a sealing unit with an axial channel or for functional inserts with autonomous instruments is embodied. The output of the pump is connected to an annular space of the tubing string, the input of a channel for supplying a working medium to the active nozzle being connected to the internal space of the tubing string above the sealing unit. A channel for removing the medium pumped out from the well is connected to the internal cavity of the tubing string below the sealing unit. Said device is also provided with a radiation source and a receiver-transducer of physical fields and a packer. The pump and a packer are arranged in the well below the casing string. The tubing string is provided with a rotating mechanism which is disposed between said pump and packer. The section of the tubing string disposed above the rotating mechanism is arranged in such a way that it is rotatable with respect to the rotating mechanism of the tubing string disposed thereunder by means of a drive arranged on the surface. Said rotating mechanism is disposed above the packer at a distance equal to or higher than the external diameter thereof. The aim of said invention is to increase the efficiency of tests and the reliability of information received during said tests.

FIELD OF THE INVENTION

The invention relates to jet devices, primarily to well jet devices andmethods of operating them, which are used for the production andintensification of oil inflow from wells.

PRIOR ART

Known in the art is a well jet device comprising a packer, a check valveand a jet pump with the active nozzle, a mixing chamber, a diffuser, thecentral channel for supplying a passive medium and a locking element,all of them being installed on the tubing string, and a geophysicalinstrument being installed on the logging cable passed through the saidlocking element (RU 2121610 C1).

The said device enables to pump various extracted media, e.g., oil, outof the well while simultaneously processing the extracted medium and theformation near-well area; but it does not enable to preclude repeatedcontamination of the formation with the working medium after stoppingthe operation of the pump unit, which narrows the field of applicationof the device.

Known in the art is a method of operating a well jet device, whichincludes lowering into the well of a tubing string with a jet pump, apacker and a radiation source and a receiver-transducer of physicalfields where the latter is arranged below the jet pump (RU 2129671 C1).

The said device enables to pump various extracted media, e.g., oil,while simultaneously studying the well, the said radiation source andthe receiver-transducer of physical fields being arranged with thepossibility of moving reciprocally along the well axis relative to thejet pump and the formation; but in a number of case this is notsufficient for obtaining full information on the well condition, whichreduces the efficacy of the work on intensifying oil production from thewell.

The closest to the invention in respect of a device, as to the technicalessence and the achieved result, is a well jet device comprising a jetpump, which is installed on the tubing string in a well with the casingstring; in the body of the said jet pump an active nozzle and a mixingchamber being coaxially arranged and a through passage being made with amounting seat for the installation of a sealing unit having an axialpassage or replaceable functional inserts with autonomous instrumentsinstalled under them; the output side of the jet pump being connected tohole clearance around the tubing string; the input side of a passage forsupplying the working medium to the active nozzle of the jet pump beingconnected to the inner cavity of the tubing string above the sealingunit; and a channel for supplying the medium pumped out of the well bythe jet pump being connected to the inner cavity of the tubing stringbelow the sealing unit; the said device being provided with a radiationsource and a receiver-transducer of physical fields and with a packerthat are installed, respectively, on the cable and on the tubing stringbelow the jet pump (RU 2129671 C1).

The said well jet unit enables to study wells. But, if the jet pump isarranged in the well below the casing string, sticking of equipmentbecomes possible due to the fact that the well walls are not fixed, and,when conducting studies in the well, in the result of pressuredifferences the risk that the well walls may collapse growssignificantly, which may result in increasing the well study time due tothe necessity of removing the jet pump to the surface for liquidatingsaid sticking, as well as the reliability of information obtained duringstudies is reduced.

The closest to the invention in respect of the method, as to thetechnical essence and the achieved result, is a method of operating awell jet device, which includes the installation on the tubing string apacker and a jet pump in the body of which a through passage with amounting seat is made, the lowering of that unit into a well, therelease of the packer and the arrangement of borehole instruments in thewell below the jet pump (RU 2129672 C1).

The said method of operating a well jet device enables to performvarious process operations in the well below the level at which the jetpump is installed, including those performed by creating a pressuredifference above and below the sealing unit. But the said well jetdevice does not enable to use its opportunities in full, which isassociated with the absence of operations aimed at precluding actionsrelated to the prevention of sticking of the tubing string with the jetpump when arranging them in a well which walls have not been fixed witha casing string.

DESCRIPTION OF THE INVENTION

The objective to be achieved with the application of this invention isto raise the working reliability and productivity while studying andtesting formations in wells with walls which have not been fixed with acasing string, as well as improving the reliability of well logginginformation obtained at early stages of well building.

The stated objective in respect of the device is achieved owing to thatthe well jet device for testing and studying formations comprises a jetpump installed on the tubing string in a well with the casing string, inthe body of the jet pump an active nozzle and a mixing chamber arecoaxially arranged and a through passage is made with a mounting seatfor installing either a sealing unit with an axial passage orreplaceable functional inserts with autonomous instruments arrangedbelow them, the output side of the jet pump is connected to the tubingstring annular space, the input side of the passage for supplying theworking medium to the active nozzle of the jet pump is connected to theinner cavity of the tubing string above the sealing unit, and thepassage for supplying the medium pumped by the jet pump out of the wellis connected to the inner cavity of the tubing string below the sealingunit, the said well jet device being provided with a radiation sourceand a receiver-transducer of physical fields and with a packer, thesebeing arranged, respectively, on the cable and on the tubing stringbelow the jet pump, the jet pump and the packer being arranged in thewell below the casing string, the tubing string being provided with arotating mechanism being arranged between the jet pump and the packer,and the section of the tubing string disposed above the rotatingmechanism being arranged with the possibility of rotating it relative tothe section of the tubing string disposed under the rotating mechanismby means of a drive arranged on the surface, and the rotating mechanismbeing arranged above the packer at a distance equal to or greater thanthe external diameter of the packer.

The stated objective in respect of the method is achieved owing to thatthe method of operating the well jet device when testing and studyingwells consists in that installed, bottom-up, are an input cone with ashank, a packer, a rotating mechanism and a jet pump, in the latter'sbody a stepwise through passage with a mounting seat between the stepsbeing made, the whole assembly is lowered on the tubing string into thewell, the said input cone being arranged not lower than the bed of theproducing formation; then the packer is released, and the section of thetubing string, which is disposed above the rotating mechanism, isrotated; then, lowered into the well, through the jet pump, are aradiation source and a receiver-transducer of physical fields togetherwith the sealing unit that is movable arranged on the logging cable or awire above the lug for connecting a radiation source and areceiver-transducer of physical fields; the sealing unit is arrangedonto the mounting seat in the through passage of the jet pump body whileensuring the possibility for reciprocal motion of the logging cable orthe wire; during the process of lowering background measurements oftemperature and other physical fields are conducted from the head to thebottom of the well; then the radiation source and thereceiver-transducer of physical fields are arranged above the bed of theproducing formation; the near-well area of the formation is cleared ofthe drilling fluid filtrate by supplying a liquid medium to the activenozzle of the jet pump, successively creating several values of pressuredrawdown on the formation and registering, at each value, well bottompressures, the composition and the physical parameters of the fluidcoming out of the producing formation as well as the well output; in thecourse of the above operations temperature anomalies emerge against theworking intervals of the formation in the result of draining the latter;then, while operating the jet pump at a set value of pressure drawdownon the formation, the radiation source and the receiver-transducer ofphysical fields are moved along the well axis in the area of theproducing formation, and the inflow profile, the parameters of theformation fluid, the well bottom pressure as well as changes of thephysical fields in the near-well and the remote areas of the formationare all registered; the possibility of performing the above operationsseveral times is provided for both at the above-mentioned set value ofpressure drawdown on the formation and at another value of pressuredrawdown on the formation; then the supply of the liquid medium to thejet pump is stopped, the radiation source and the receiver-transducer ofphysical fields together with the logging cable and the sealing unit areremoved out of the well, and the section of the tubing string disposedabove the rotating mechanism is rotated; then, lowered along the tubingstring and installed on the mounting seat of the through passage is aninsert for recording curves of formation pressure restoration in theunder-packer area of the well, the said insert being lowered togetherwith a sampler and an autonomous instrument provided with a pressuresensor, a temperature sensor, a flow rate sensor, a formation fluidcomposition sensor, etc.; then a necessary pressure drawdown on theformation is created by supplying the liquid medium to the nozzle of thejet pump, and after the set time of draining the producing formation thesupply of the liquid medium to the jet pump nozzle is stopped abruptly,and after the set time of recording a curve of formation pressurerestoration in the under-packer area of the well the functional insertfor recording curves of formation pressure restoration is removedtogether with the sampler and the autonomous instrument; the section ofthe tubing string disposed above the rotating mechanism is rotated onceagain; and the jet pump together with its assembly is removed out of thewell to the surface.

In a number of cases studies and tests of formations in wells are to becarried out in sections where the casing string is not installed. As aresult, it is necessary to arrange a jet pump and a packer below thecasing string, in the area with non-fixed well walls. Pressuredifferences, which are formed in the well at, e.g., creating a pressuredrawdown or in the result of pumping the medium out of the under-packerarea of the well, collapses of well walls are possible, which results insticking the equipment being in the well. It primarily relates to thetubing string and the jet pump arranged under the packer. As theconducted studies show, regular rotation of the section of the pipingstring with the jet pump arranged above the packer enables to avoidtheir sticking in the course of studying the well after releasing thepacker and after removing the radiation source and thereceiver-transducer of physical fields out of the well. It is associatedwith the fact that in the process of rotating the tubing string it ispossible to preclude forming a dense obstruction consisting ofcollapsing rocks, which enables to arrange for removal of the collapsingrocks onto the surface together with the fluid flow discharging from thejet pump. Furthermore, regular rotation of the tubing string togetherwith the jet pump enables to avoid sticking of the tubing string withthe jet pump to the well walls, which eliminates the necessity toperform additional works on cleaning the well and, consequently, toreduce the time for studying and testing formations in wells with wallsnot fixed with a casing string.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a lengthwise section of the well jet device in the process oftesting a well with an radiation source and a receiver-transducer ofphysical fields installed.

FIG. 2 is a lengthwise section of the well jet device in the process oftesting a well with an installed insert for recording curves offormation pressure restoration in the under-packer area of a well.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

The inventive well jet device for realization of the described methodcomprises the jet pump 1 installed on the tubing string 2 in the wellwith the intermediate casing string 3 and the open borehole 20. In thebody 4 of the jet pump 1 the active nozzle 5 and the mixing chamber 6are coaxially arranged and the through passage 7 is made with a mountingseat 16 for installing either the sealing unit 8 with the axial passage21 or the insert 15 for recording curves of formation pressurerestoration together with the sampler 22 and the autonomous instrument23 provided with a pressure sensor, a temperature sensor, a flow ratesensor, a formation fluid composition sensor, etc. The device isprovided with the radiation source and the receiver-transducer ofphysical fields 10 installed on the logging cable or the wire 9 andarranged below the jet pump 1. The output side of the jet pump 1 isconnected to the annular space of the tubing string 2, the input side ofthe passage 12 for supplying the working medium to the active nozzle 5is connected to the inner cavity of the tubing string 2 above thesealing unit 8, and the passage 11 for supplying the medium pumped outof the well by the jet pump 1 is connected to the inner cavity of thetubing string 2 below the sealing unit 8. The packer 13 is arranged onthe tubing string 2 below the jet pump 1. The jet pump 1 and the packer13 are arranged in the well below the casing string 3. The tubing string2 is provided with the rotating mechanism 14 arranged between the jetpump 1 and the packer 13. The section of the tubing string 2 above therotating mechanism 14 is arranged with the possibility of being rotatedrelative to the tubing string section disposed below the rotatingmechanism 14 with the use of the drive located on the surface, and therotating mechanism 14 is arranged above the packer 13 at the distance Lwhich is equal to or greater than the external diameter D of the packer13.

The described method of operating the well jet device in studying andtesting wells is realized as follows.

The jet pump 1 and arranged below the jet pump 1 the rotating mechanism14, the packer 13 and the input cone with the shank 17 are installed onthe tubing string 2 in the well. Then the packer is released in theannular space of the tubing string 2, which enables to separate the wellspace. The section of the tubing string 2, as arranged above therotating mechanism 14, is rotated. Then the radiation source and thereceiver-transducer of physical fields 10 are connected to the lug 24 ofthe logging cable or the wire, and the sealing unit 8 is arranged on thecable or the wire 9 with the possibility of reciprocal motion of thelogging cable or the wire 9, and this assembly is lowered into the innercavity of the tubing string 2. In the process of lowering backgroundmeasurements of temperature and other physical fields are made from thehead to the bottom of the well. After this a liquid working medium issupplied through the tubing string 2 to the active nozzle 5 of the jetpump 1, which enables to start pumping the formation medium out of theunder-packer area with the use of the jet pump 1. Thus the producingformation 18 is drained and near-well area 19 of the formation 18 iscleared of the drilling fluid filtrate, which results in emergingtemperature anomalies in the interval of the working sections of theproducing formation 18. The parameters in the under-packer area of thewell are monitored with the use of the radiation source and thereceiver-transducer of physical fields 10, while successively creatingdifferent values of pressure drawdown on the formation, registering, ateach value, well bottom pressures, the composition and the physicalparameters of the fluid coming out of the producing formation as well asthe well output. Then, while operating the jet pump 1 at a set value ofpressure drawdown on the formation 18, the radiation source and thereceiver-transducer of physical fields 10 are moved along the well axisin the area of the producing formation 18, and the inflow profile, theparameters of the formation fluid, the well bottom pressure as well aschanges of the physical fields in the near-well area and the remote area(the well area located beyond the near-well area) of the formation areregistered, the possibility of performing the above operations isprovided for several times both at the above-mentioned set value ofpressure drawdown on the formation and at another value of pressuredrawdown on the formation. Then the supply of the liquid medium to thejet pump 1 is stopped, the radiation source and the receiver-transducerof physical fields 10 together with the logging cable or the wire 9 andthe sealing unit 8 are removed out of the well. The section of thetubing string 2 with the jet pump 1 is rotated with the use of the drivelocated on the surface, which prevents them from being stuck in the welldue to collapse of the well walls. Then, lowered along the tubing string2 and installed on the mounting seat 16 in the through passage 15 is aninsert for recording curves of formation pressure restoration in theunder-packer area of the well, the said insert being lowered togetherwith the sampler 22 and the autonomous instrument 23 provided with apressure sensor, a temperature sensor, a flow rate sensor, a formationfluid composition sensor, etc. The formation fluid is pumped out and thenecessary pressure drawdown on the formation 18 is created with the jetpump 1, and after the set time of draining the producing formation thesupply of the liquid medium to the nozzle 5 of the jet pump 1 is stoppedabruptly. A curve of formation pressure restoration in the under-packerarea of the well is recorded, and the section of the tubing string 2disposed above the rotating mechanism 14 is rotated once again, afterwhich the insert 15 is extracted and then the jet pump 1 with the wholeassembly is removed out of the well to the surface.

INDUSTRIAL APPLICABILITY

This invention may be applied in the oil production industry or themining industry for testing and studying oil or gas wells at the stageof drilling.

1. A well jet device for testing and studying formations, comprising ajet pump installed on the tubing string in a well with the casingstring, in the body of the jet pump an active nozzle and a mixingchamber are coaxially arranged and a through passage is made with amounting seat for installing either a sealing unit with an axial passageor replaceable functional inserts with autonomous instruments arrangedbelow them, the output side of the jet pump being connected to thetubing string annular space, and the input side of the passage forsupplying the working medium to the active nozzle of the jet pump beingconnected to the inner cavity of the tubing string above the sealingunit, and the passage for supplying the medium pumped by the jet pumpout of the well being connected to the inner cavity of the tubing stringbelow the sealing unit, the said well jet device being provided with aradiation source and a receiver-transducer of physical fields and with apacker, these being arranged, respectively, on the cable and on thetubing string below the jet pump, the jet pump and the packer beingarranged in the well below the casing string, the tubing string beingprovided with a rotating mechanism being arranged between the jet pumpand the packer, and the section of the tubing string disposed above therotating mechanism being arranged with the possibility of rotating itrelative to the section of the tubing string disposed under the rotatingmechanism by means of a drive arranged on the surface, and the rotatingmechanism being arranged above the packer at a distance equal to orgreater than the external diameter of the packer.
 2. A method ofoperating a well jet device when testing and studying wells, consistingin installing, bottom-up, an input cone with a shank, a packer, arotating mechanism and a jet pump, wherein in the latter's body astepwise through passage with a mounting seat between the steps isprovided, lowering the whole assembly on the tubing string into thewell, the said input cone being arranged not lower than the bed of theproducing formation, then releasing the packer, and rotating the sectionof the tubing string, which is disposed above the rotating mechanism,then, lowering into the well, through the jet pump, a radiation sourceand a receiver-transducer of physical fields together with a sealingunit that is movable arranged on a logging cable or a wire above the lugfor connecting said radiation source and receiver-transducer of physicalfields; arranging the sealing unit onto the mounting seat in the throughpassage of the jet pump body while ensuring the possibility forreciprocal motion of the logging cable or the wire; during the processof lowering making background measurements of temperature and otherphysical fields from the head to the bottom of the well, then arrangingthe radiation source and the receiver-transducer of physical fieldsabove the bed of the producing formation, clearing the near-well area ofthe formation of the drilling fluid filtrate by supplying a liquidmedium to the active nozzle of the jet pump while successively creatingseveral values of pressure drawdown on the formation and registering, ateach value, well bottom pressures, the composition and the physicalparameters of the fluid coming out of the producing formation as well asthe well output, then, while operating the jet pump at a set value ofpressure drawdown on the formation, moving the radiation source and thereceiver-transducer of physical fields along the well axis in the areaof the producing formation, and registering the inflow profile, theparameters of the formation fluid, the well bottom pressure as well aschanges of the physical fields in the near-well and the remote areas ofthe formation; wherein the above operations are optionally performedseveral times for both at the above-mentioned set value of pressuredrawdown on the formation and at another value of pressure drawdown onthe formation, then stopping the supply of the liquid medium to the jetpump, removing out of the well the radiation source and thereceiver-transducer of physical fields together with the logging cableand the sealing unit, and rotating the section of the tubing stringdisposed above the rotating mechanism, then, lowering along the tubingstring and installing on the mounting seat of the through passage aninsert for recording curves of formation pressure restoration in theunder-packer area of the well, lowering the said insert together with asampler and an autonomous instrument provided with a pressure sensor, atemperature sensor, a flow rate sensor, a formation fluid compositionsensor, creating a necessary pressure drawdown on the formation bysupplying the liquid medium to the nozzle of the jet pump, and after theset time of draining the producing formation abruptly stopping thesupply of the liquid medium to the jet pump nozzle, and after the settime of recording a curve of formation pressure restoration in theunder-packer area of the well removing the functional insert forrecording curves of formation pressure restoration together with thesampler and the autonomous instrument, rotating once again the sectionof the tubing string disposed above the rotating mechanism, and removingthe jet pump together with its assembly out of the well to the surface.